Side-loading bone anchor

Abstract

A side-loading bone anchor is provided, which may be used in cervical, thoracic, lumbar or sacral areas of the spine or other orthopedic locations. In one embodiment, the anchor includes an anchoring portion and a receiving portion. The anchoring portion is attached to a bone, and is connected to the receiving portion. A rod or other elongated support member is received in the receiving portion in contact with a crown member in the receiving portion and above the anchoring portion. The receiving portion, with or without the rod, may be rotated or pivoted with respect to the anchoring portion, and a set screw is threaded into the receiving portion to lock the rod within the receiving portion.

1. A side-loading vertebral anchor comprising:
 a C-shaped receiving portion having an upper leg, a base, and an intermediate portion, said receiving portion forming an open channel, said base having an aperture therethrough with a longitudinal axis and a groove communicating with said aperture, said groove substantially surrounding said aperture, said base further having a sloped or curved surface adjacent said channel, said surface ending in a ridge; 
 an expandable and contractible clip member at least partially within said groove, said clip member having an internal dimension; 
 an anchor portion having a head portion and a shaft portion, said head portion being at least partially within said aperture in said base of said receiving portion and adjacent said clip member, said head portion having an external dimension at least slightly larger than said internal dimension of said clip member whereby said clip member prevents passage of said head portion beyond said clip member, wherein said head of said anchor portion includes a groove, and at least a portion of said clip member is within at least a portion of said groove of said head portion; 
 whereby an elongated member can be inserted from the side of said receiving portion into said channel in a direction substantially toward said intermediate portion and substantially perpendicular to said axis of said aperture in said base portion. 
 
   
   
     2. An apparatus according to  claim 1 , wherein said anchor portion has a longitudinal axis, and said anchor portion is rotatable around said axis with respect to said base of said receiving portion. 
   
   
     3. An apparatus according to  claim 1 , wherein said head of said anchor portion is substantially hemispherical. 
   
   
     4. An apparatus according to  claim 1 , further comprising a longitudinal member in said channel and in contact with said head, and a set screw threaded through said upper leg and against said longitudinal member whereby said longitudinal member, said anchor portion and said receiving portion are locked together. 
   
   
     5. A side-loading vertebral anchor comprising:
 a C-shaped receiving portion having an upper leg, a base, and an intermediate portion, said receiving portion forming an open channel, said base having an aperture therethrough with a longitudinal axis and a groove communicating with said aperture, said groove substantially surrounding said aperture, said base further having a sloped or curved surface adjacent said channel, said surface ending in a ridge; 
 an expandable and contractible clip member at least partially within said groove, said clip member having an internal dimension; 
 an anchor portion having a head portion and a shaft portion, said head portion being at least partially within said aperture in said base of said receiving portion and adjacent said clip member, said head portion having an external dimension at least slightly larger than said internal dimension of said clip member whereby said clip member prevents passage of said head portion beyond said clip member, wherein said head of said anchor portion contacts an upper surface of said clip member, whereby said anchor portion is multi-axially rotatable with respect to said base; and 
 a crown member at least partially within said aperture of said base, said crown member having an upper undulating portion including a top surface facing said upper leg of said receiving portion, a lower portion and an aperture through said upper and lower portions, said top surface of said undulating portion having a substantially cylindrical convex top surface portion to one side of said undulating portion and a substantially cylindrical concave top surface portion to the other side of said undulating portion, said crown member aperture having a substantially spherical lower portion, wherein said substantially spherical lower portion is adjacent said head of said anchor portion; and 
 whereby an elongated member can be inserted from the side of said receiving portion into said channel in a direction substantially toward said intermediate portion and substantially perpendicular to said axis of said aperture in said base portion. 
 
   
   
     6. An apparatus according to  claim 5 , wherein a portion of said crown member extends into said channel. 
   
   
     7. An apparatus according to  claim 5 , further comprising a longitudinal member in said channel and in contact with said crown member, and a set screw threaded through said upper leg and against said longitudinal member whereby said longitudinal member, said crown member, said anchor portion and said receiving portion are locked together. 
   
   
     8. An apparatus according to  claim 5 , wherein said receiving portion includes at least one protrusion for accommodating a tool portion, said protrusion being substantially oval shaped and parallel to an underside of said upper leg. 
   
   
     9. A side-loading vertebral anchor comprising:
 a C-shaped receiving portion having an upper leg, a base, and an intermediate portion, said receiving portion forming an open channel, said base having an aperture therethrough with a longitudinal axis and a groove communicating with said aperture, said groove substantially surrounding said aperture, said base further having a sloped or curved surface adjacent said channel, said surface ending in a ridge, wherein said receiving portion includes at least one indentation for receiving a tool portion, said indentation having an entry portion, a holding portion with a substantially circular part, and a corner between said holding portion and said entry portion, whereby a tool portion may be inserted through said entry portion in one direction and into said holding portion in another direction; 
 an expandable and contractible clip member at least partially within said groove, said clip member having an internal dimension; 
 an anchor portion having a head portion and a shaft portion, said head portion being at least partially within said aperture in said base of said receiving portion and adjacent said clip member, said head portion having an external dimension at least slightly larger than said internal dimension of said clip member whereby said clip member prevents passage of said head portion beyond said clip member; 
 whereby an elongated member can be inserted from the side of said receiving portion into said channel in a direction substantially toward said intermediate portion and substantially perpendicular to said axis of said aperture in said base portion. 
 
   
   
     10. An apparatus for attachment to a vertebra and a longitudinal member, comprising:
 a bone anchor portion having a head portion, a threaded shaft and a non-threaded neck, said threaded shaft having cancellous threads suited to connection to a vertebra; 
 a substantially C-shaped receiving portion having a base portion, an upper leg and an intermediate portion, said receiving portion including an internally threaded aperture through said upper leg, said receiving portion further including a hole in said base portion having a longitudinal axis, said receiving portion having a channel substantially perpendicular to said axis into which a longitudinal member can be placed in said receiving portion, said receiving portion further including a groove communicating with said hole, said receiving portion further including an open hook-shaped exterior imprint for accommodating a holding tool so that a holding tool can be slid into said hook-shaped imprint; 
 a crown member at least partially within said hole in said receiving portion, said crown member having an upper undulating portion including a top surface facing said upper leg of said receiving portion, a lower portion and an aperture through said upper and lower portions, said top surface of said undulating portion having a substantially cylindrical convex top surface portion to one side of said undulating portion and a substantially cylindrical concave top surface portion to the other side of said undulating portion, said crown member aperture having a substantially spherical lower portion; and 
 a ring member around at least a portion of said bone anchor such that at least a portion of said ring member is within said groove, said ring member having an internal dimension at least slightly smaller than said head portion so that said head portion of said bone anchor portion and said ring member cannot be withdrawn from said hole of said receiving portion. 
 
   
   
     11. The apparatus of  claim 10 , wherein said receiving portion includes an abutment adjacent said hole and said channel that prevents said crown member from exiting said hole into said channel. 
   
   
     12. The apparatus of  claim 10 , wherein said head portion of said bone anchor portion includes at least one ridge. 
   
   
     13. The apparatus of  claim 10 , wherein said channel has a substantially cylindrical portion, and said receiving portion has a front sloped or curved surface leading into said channel, said surface ending in a ridge near said substantially cylindrical portion of said channel. 
   
   
     14. An apparatus according to  claim 10 , wherein said receiving portion includes at least one protrusion for accommodating a tool portion, said protrusion being substantially oval shaped and parallel to an underside of said leg portion. 
   
   
     15. An apparatus according to  claim 10 , wherein a longitudinal member is placed in said channel and in contact with said crown member, and further comprising a set screw threaded into said upper leg and against said longitudinal member whereby said longitudinal member, said crown member, said anchor portion and said receiving portion are locked together. 
   
   
     16. An apparatus for attachment to a vertebra and a longitudinal member, comprising:
 a bone anchor portion having a head portion, a threaded shaft and a non-threaded neck, said threaded shaft having cancellous threads suited to connection to a vertebra; 
 a substantially C-shaped receiving portion having a base portion, an upper leg and an intermediate portion, said receiving portion including an internally threaded aperture through said upper leg, said receiving portion further including a hole in said base portion having a longitudinal axis, said receiving portion having a channel substantially perpendicular to said axis into which a longitudinal member can be placed in said receiving portion, said receiving portion further including a groove communicating with said hole, said receiving portion further including an open hook-shaped exterior imprint for accommodating a holding tool so that a holding tool can be slid into said hook-shaped imprint, wherein said receiving portion includes at least one indentation for receiving a tool portion, said indentation having an entry portion, a holding portion with a substantially circular part, and a corner between said holding portion and said entry portion, whereby a tool portion may be inserted through said entry portion in one direction and into said holding portion in another direction; 
 a crown member at least partially within said hole in said receiving portion, said crown member having an upper undulating portion, a lower portion and an aperture through said upper and lower portions, said undulating portion having a substantially cylindrical convex portion to one side of said undulating portion and a substantially cylindrical concave portion to the other side of said undulating portion, said crown member aperture having a substantially spherical lower portion; and 
 a ring member around at least a portion of said bone anchor such that at least a portion of said ring member is within said groove, said ring member having an internal dimension at least slightly smaller than said head portion so that said head portion of said bone anchor portion and said ring member cannot be withdrawn from said hole of said receiving portion. 
 
   
   
     17. An apparatus comprising:
 a receiving member for receiving a longitudinal member, said receiving member having a channel opening to the side, an upper threaded aperture and a lower aperture each communicating with said channel, said lower aperture having a lower opening and an upper opening, said upper opening adjacent said channel, said receiving member further including a groove communicating with said lower aperture; 
 an anchor member having a longitudinal axis and a head with an external surface and an internal imprint, said head being at least partially inserted through said lower opening and into said lower aperture, said head further including a groove in said external surface; and 
 a C-shaped ring member at least partially within said groove of said receiving member and at least partially within said groove of said head, whereby said anchor member is rotatable about said axis of said anchor member with respect to said receiving member. 
 
   
   
     18. An apparatus according to  claim 17 , further comprising a set screw for threading into said threaded aperture of said receiving member. 
   
   
     19. An apparatus according to  claim 18 , further comprising a longitudinal member within said channel and adjacent said head, wherein threading said set screw causes said set screw to contact said longitudinal member and lock said apparatus. 
   
   
     20. An apparatus according to  claim 18 , wherein said receiving member includes at least one indentation for receiving a tool portion, said indentation having an entry portion, a holding portion with a substantially circular part, and a corner between said holding portion and said entry portion, whereby a tool portion may be inserted through said entry portion in one direction and into said holding portion in another direction. 
   
   
     21. An apparatus according to  claim 20 , wherein said receiving member includes at least one protrusion for accommodating a tool portion, said protrusion being substantially oval shaped and parallel to an upper portion of said channel.